Make sure sockets are shutdown in java viewer listen mode

The finalizer method may not be strictly necessary but for the sake
of consistency shutdown the socket listener the same way we do for
a regular TcpSocket.

java/com/tigervnc/network/SocketListener.java

@@ -29,7 +29,7 @@ abstract public class SocketListener {
   public SocketListener() {}
 
   // shutdown() stops the socket from accepting further connections
-  abstract public void shutdown();
+  abstract public void shutdown() throws Exception;
 
   // accept() returns a new Socket object if there is a connection
   // attempt in progress AND if the connection passes the filter

java/com/tigervnc/network/TcpListener.java

@@ -84,12 +84,21 @@ public class TcpListener extends SocketListener  {
     this(listenaddr, port, false, null, true);
   }
 
-//  TcpListener::~TcpListener() {
-//    if (closeFd) closesocket(fd);
-//  }
+  protected void finalize() throws Exception {
+    if (closeFd)
+      try {
+        ((SocketDescriptor)getFd()).close();
+      } catch (IOException e) {
+        throw new Exception(e.getMessage());
+      }
+  }
 
-  public void shutdown() {
-    //shutdown(getFd(), 2);
+  public void shutdown() throws Exception {
+    try {
+      ((SocketDescriptor)getFd()).shutdown();
+    } catch (IOException e) {
+      throw new Exception(e.getMessage());
+    }
   }
 
   public TcpSocket accept() {